Likely situations for saltbush & understorey

 

1.     Salinity and waterlogging
The ‘saltbush & understorey’ option performs best where the site will grow understorey legumes. That is sites of moderate salinity (ECe 4-8 dS/m) in the 250-400mm rainfall zone, but it can also be recommended for sites of low salinity (ECe 2-4 dS/m) if the rainfall is too low to support perennial grasses like tall wheatgrass, tall fescue and phalaris.

For sites with high salinity (ECe 8-16 dS/m), a sown under-storey is unlikely to be more productive than an under-storey of volunteer species and the savings on under-storey seed, sowing and fertilising can be put into a higher density of saltbush.

Most likely situations for saltbush & understorey

Subsoil salinity/ depth to watertable matrix

 Winter

Summer 

 

 

Drivers of plant zonation

  • Halophyte (saltbush) and non-halophytes (under-storey) with differing tolerances to waterlogging.
  • Compromises required!
  • Saltbush growth in summer assisted if roots can access groundwater;
  • Most likely rainfall - 300-450mm

 


Key to symbols

red dot

This is the zone most preferred by saltbush and where it is highly recommended;

Small Dot

Saltbush is one of the possible options for this zone but it is outside its preferred conditions;

red ring

Saltbush will most likely survive in this zone, but its growth will be poor and therefore it is not recommended.


2.     Climate and soils
Waterlogging is the most significant soil limitation for saltbush growing on saline land and it also restricts the use of some understorey legumes. Saltbushes prefer alkaline soils but understorey species are available for both acid and alkaline soils. The saltbush can only be successfully direct seeded if there is a sandy or loamy surface.

Rainfall is the key climatic feature and the recommended zone is approximately 300-450 mm. For wetter sites, with moderate and high salinities, the salt-tolerant grasses (especially tall wheatgrass and puccinellia) provide a more productive and persistent option.

3.     Indicator species
Sites that are suitable for saltbush & understorey are a compromise between where saltbush will grow and where the sown understorey species can make a better contribution than volunteer pasture. Such sites will probably have a mixture of capeweed, annual ryegrass, barley grass and sea barleygrass.

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